1. 04 Dec, 2009 1 commit
  2. 01 Aug, 2009 1 commit
  3. 22 May, 2009 1 commit
    • Martin K. Petersen's avatar
      block: Export I/O topology for block devices and partitions · c72758f3
      Martin K. Petersen authored
      
      To support devices with physical block sizes bigger than 512 bytes we
      need to ensure proper alignment.  This patch adds support for exposing
      I/O topology characteristics as devices are stacked.
      
        logical_block_size is the smallest unit the device can address.
      
        physical_block_size indicates the smallest I/O the device can write
        without incurring a read-modify-write penalty.
      
        The io_min parameter is the smallest preferred I/O size reported by
        the device.  In many cases this is the same as the physical block
        size.  However, the io_min parameter can be scaled up when stacking
        (RAID5 chunk size > physical block size).
      
        The io_opt characteristic indicates the optimal I/O size reported by
        the device.  This is usually the stripe width for arrays.
      
        The alignment_offset parameter indicates the number of bytes the start
        of the device/partition is offset from the device's natural alignment.
        Partition tools and MD/DM utilities can use this to pad their offsets
        so filesystems start on proper boundaries.
      Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      c72758f3
  4. 03 Jul, 2008 1 commit
  5. 08 Feb, 2008 1 commit